Google Play is catching up to the Apple App Store by some metrics, but still has a ways to go, according to a year-end study by Dutch analytics firm Distimo. Both stores now have over 700,000 apps, but the App Store generates about 4.3 times more revenue than Google Play. "On a typical day in November 2012, the revenues in the Apple App Store exceeded $15M USD, while in Google Play the revenues are just below $3.5M USD in 20 of the largest countries in both app stores," Distimo writes.

Google Play revenue did, however, grow an aggregated 43 percent in the last four months, beating Apple's pace of 21 percent. Distimo notes that in January Apple's daily revenue jumped about 51 percent, split between 71 percent for the iPad and 40 percent for the iPhone.

Russia appears to be growing fastest in terms of iPad app consumption, rising 143 percent year-over-year. Japan is doing best with iPhone apps (up 138 percent), while South Korea has seen the highest Android app surge, up 94 percent.

The nature of sales is evolving on both the App Store and Google Play. Google Play apps are more expensive as a rule, but the average selling price of iPhone apps has risen 16 percent since January at the same time as iPad apps have dropped 8 percent. In-app purchases have become increasingly important to Apple; they were already generating 53 percent of App Store revenue in January, but by November accounted for 69 percent. One-time sales do matter, since they produced 35 percent of the revenue among the top 10 App Store moneymakers.

In January, 11 apps spawned 10 percent of all App Store revenues. That money came into even fewer hands by November, when just seven apps pulled in the same kind of cash.